回顾感应加热弯管标准编制的发展历程并介绍标准的重要内容,分析感应加热弯管外弧侧壁厚减薄率C计算公式的符号含义;分析感应加热弯管和钢板加热压制组焊弯管成形前后壁厚与应力变化,指出当前油气输送管道设计规范关于热煨弯管壁厚设计计算存在的分歧,提出变壁厚弯管和等壁厚弯管概念及其应力分布和壁厚计算方法;以ASME B31.3—2010《工艺管道》关于弯管壁厚计算公式的规定和感应加热弯管水压爆破试验启裂口位置实例予以佐证。建议相关设计规范对热煨弯管壁厚计算公式予以修改和完善。以热煨弯管应力分布状态和弯管强度条件下的危险位置为依据,提出双壁厚弯管概念和结构。

Reflecting on the evolution of standards for induction heating bent pipe development, this paper introduced the key aspects of these standards and interprets the symbols in the formula for the wall thickness reduction rate C on the outer arc side of induction heating bent pipes. By analyzing the variation trend of wall thickness and stress before and after pipe bending process for both induction heating bent pipes and steel plate heating pressed welded bent pipes, this paper showed the discrepancies on wall thickness calculation for heating bent pipe in current standards. This paper also provided concepts for variable and constant wall thickness bent pipe, along with their calculation methods for stress distribution and wall thickness. It substantiates these points with cases from ASME B31.3-2010 Process piping regarding bent pipe wall thickness calculation formula and the location of initiation cracks from hydraulic burst test on induction heating bent pipes. On this basis, this paper suggests revising the bent pipe wall thickness calculation formulae in relevant standards. This paper provides concept and structure for dual wall thickness bent pipe based on the hazardous location under stress distribution and strength condition.